1. Field of Invention
The invention relates to a display system and a display method and, in particular, to a display system, which is adaptable to changes in video signals of a display region thereof according to display aspect ratios of input video signals, and a method thereof.
2. Related Art
Nowadays, various new display systems have been configured to have a wide screen with the aspect ratio of 16:9 so as to show the typical effect of a movie screen. The aspect ratio of 16:9 is the golden ratio which can meet the human visual system, such that the best wide field and the better visual effect can be obtained.
In a typical main medium of “television” for home entertainment, a so-called wide television is produced. However, many current video signals, such as an analog television signal, a standard definition (SD) digital television signal, and the like, still pertain to the conventional screen with the aspect ratio of 4:3, which is different from that of the present wide television. Thus, the wide television adopts two methods to solve the problem.
The first method is referred to as a pan and scan (full screen) mode, in which the display aspect ratio (4:3) of the video signal is changed, such that the wide televisions may be fully filled with the video screen. However, this method obviously distorts and deforms the display screen, as shown in FIG. 1(a).
The second method is referred to as a letter box mode, in which the display aspect ratio (4:3) of the video signal is kept and two blank portions at two sides of the wide television are filled with black levels. However, this method produces two obvious black sides at the left and right sides of the screen, as shown in FIG. 1(b).
The visual effects of the deformed screen in the pan and scan mode or of the two black sides in the letter box mode cannot satisfy most users when they are watching the screen of the original video signal with the aspect ratio of 4:3. Due to the popularization of the wide television but the video signal having the aspect ratio of 4:3 is still the mainstream, more and more users will encounter such a problem. Thus, it is very important to provide the technology for solving the problem of uncomfortable visual feeling.
Therefore, it is an important subject of the invention to provide a display system adaptable to changes in video signals and a method thereof because the current display system still has the drawback in displaying the video signals with different aspect ratios.